Patents by Inventor Philip J. Davidson

Philip J. Davidson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Filter for converting pulse width modulation to amplitude modulation
    Patent number: 4250469
    Abstract: In a high efficiency amplitude modulation circuit. A pulse width modulation switch is arranged with a low pass filter to attentuate switching frequencies of the switch. A diode is connected in parallel with the input terminals of the low pass filter which diode provides a current discharge path for the filter while the switch is non-conductive. A further filter is also connected in parallel with the input terminals of the low pass filter, this further filter being arranged to provide cancellation of the input susceptance of the low pass filter over at least part of its pass band. The two filters in combination are such as to present a constant input conductance over at least part of the pass band of the low pass filter.
    Type: Grant
    Filed: March 2, 1979
    Date of Patent: February 10, 1981
    Assignee: The Marconi Company, Limited
    Inventors: David Cooper, Philip J. Davidson